[RioRico]

I don't understand how those cheap adapters can claim that they can still focus to infinity.

Oh, they'll infinity-focus, all right. It's just that their optics make the final image suck.

Has anyone had any kind of bad experience trying something like this like a lens getting stuck?

Rather the opposite. I've hung Nikkors on my K20D and ZX-M mounts with no problem. But If I try to insert a Nikkor into a generic PK mount, such as a Vivitar telextender or some cheap Hong Kong macro tube sets, the Nikkors won't fit snugly. That is, they fall off. It was most instructive, looking at the underside of the mount piece from the macro set, to see just where the F-mount didn't fit. It's like getting a camera's-eye-view of the lens base.

[ManixZero]

I found this Nikon-Pentax adapter online today. Has anyone tried it?

I use a similar adapter to mount my Micro-Nikkor 55mm to my K100D. With the glass inside the IQ suffered and there was noticeable flare in the centre of the image from f8. I did focus to infinity.

I removed the glass to see how things improved - I lost the infinity focus (of course) gained a little closer focus and regained the high IQ of the lens

I threw the glass away to rmove the temptation of ever refitting it and now enjoy my PK/AI adaper extension ring.

Don't be tempted if you don't want to lose either the glass or the IQ

Cheers MZ

[fine_idea]

While Sean Carpenter's (online name Carpents) 2006 thread "Using Nikon F Lenses On Pentax K Bodies" in dpreview (Using Nikon F Lenses On Pentax K Bodies (LBA Post) [Page 1]: Pentax SLR Talk Forum: Digital Photography Review) no longer shows his sample pictures taken with Nikon glass on a Pentax, you can find a link to his pictures online further down in that thread or you can see them on his pbase.com site at Equipment Photo Gallery by Sean Carpenter at pbase.com. Click a lens and you can see a gallery of his shots there.

He suggests that Pentax owners can do something Nikon owners can't: use pre-AI Nikkor lenses. Nikon DSLR mount don't allow that.

More about pre-AI lenses: "A note on fitting the lenses: You have to align the dot on the Nikon lens with about the 2:00 position as you look at the camera mount. It will slide down fully. Then, you give it a slight clockwise turn - this is where the AI lenses barely fit on but most of the Non-AI lenses turn about 1/16th of a turn which is more than enough to get a firm fit. Like I said earlier, the 55 Micro and 24mm turn far enough that they actually clear the locking pin, and they 'click' into place. None of the others fit like that, though.


It is a somewhat delicate operation at first, but as long as you don't force it - they fit."


More about AI lenses: "Be warned that the AI lenses don't work so well - the have a different flange at the bottom that makes them not fit so well (at least my 20/3.5 AI is this way.) But, I'm sure the modification to full-blown K-mount isn't too terribly hard."


This is a fascinating subject. In the meantime if you want more information about this subject, do read the complete thread of Sean's dpreview post as he goes on to describe things like how he modified an M42-K adapter then fit it onto a Nikon lens. Clever guy!

[boriscleto]

Gah! Thread necromancy. This thread died a year ago.

[RioRico]

Old threads never die, eh?

A little searching here will find multiple versions of my accounts of quickly modding N/AI lenses for PK-mount force-fit. I just chopped another one this afternoon. It took me about three (3) minutes. There's too much snow to work on my backstairs railing, my usual workshop, so I did it over the bathroom sink, just me and the Dremel #426 blade. Whoopee!

[selar]

Will a 24/2.8 Auto N Nikkor fit without issues? Pre AI.

[Wombat]

There aren't enough old Pentax lenses out there? Shame on you!

[selar]

There aren't enough old Pentax lenses out there? Shame on you!

Take it easy, I bought a couple of Taks today along with a Spotmatic.

[RioRico]

Will a 24/2.8 Auto N Nikkor fit without issues? Pre AI.

I'd have to see it to be sure, but probably yes.

I've encountered three types of Nikon-mount manual lenses: 1) a full (thin) skirt around the aperture ring; 2) no skirt around the aperture ring; and 3) aperture ring has what I call a "nub and arc" structure. Type (2) was a 3rd-party lens. I assume types (1) and (2) are pre-AI, and type (3) is AI or AIS.

All these can more-or-less be force-fit onto a Pentax mount. (A fourth type I tried, on an AF lens, would NOT force-fit, and I didn't bother with it.) Type (2) (no skirt) is no problem at all, and safely shorts the PK mount contacts so CIF is usable. Type (1) (full skirt) is a bit insecure, especially with longer lenses -- a 200/3.5 is right at the limit of comfort for me. Type (3) is a bit clumsy unmodified -- these are the lenses upon which I perform minor surgery, dremeling-off the "nub and arc" structure, which also gives me CIF usage.

"Force-fit" means just that: the lens isn't securely locked on. I may cut a small slot in NI lens bases for the PK-mount locking pin to engage, for more security. But mostly, I just handle these rigs fairly carefully. Haven't lost one yet!!

[El Pentaxero]

would a Vivitar Serie 1 135mm for Nikon fit in a Pentax K or should i get an adapter?

[RioRico]

would a Vivitar Serie 1 135mm for Nikon fit in a Pentax K or should i get an adapter?

You can get an optical adapter. It will probably turn a 135/2.8 lens into something towards 170/3.5 -- such adapters are short teleconverters.

You can remove the glass from an optical addpter; the lens remains 135/2.8. But it will not focus to infinity and can only be used for closeups.

Depending on exactly which Nikon F-mount the your lens has, it *should* fit but it might need some modification -- cutting off little metal bits.

Optical adapters lower image quality. Non-optical adapters lose infinity focus. Chopping lenses reduces resale value. Just buy the right lens.

[RonHendriks1966]

I have an adapter to fit Nikon on Pentax. Don't have any Nikon lenses anymore, since my last sales. It works like a TC with magnification of about 1,25. So my 300mm/f4.5 became a 375mm/f5.6 manual lens

So when you have a real good lens it is worth to purchase. There is also a way of making the Nikon fit by turning it and putting it on. You can also drill some space to have it clicked proparly, but never done that myself.


K-7 and Nikkor pre-AI 300mm/f4.5

Justin Henin at WTA tournament in Rosmalen 2010.

[El Pentaxero]

So i guess a 135mm 2.3 will be a 170mm 2.9 with the use of that adapter? am i right?

[ripit]

There is no reason an adapter like this couldn't be made with minimal quality loss but to the best of my knowledge there are no good quality ones. Its got glass and is basically a lens of sorts. What kind of image quality would you expect from a 30$ Chinese lens? I have yet to see or hear about any better ones though. I have seen the massa brand mentioned a few times and get the impression that it might be among the better of the cheap Chinese ones, but I wouldn't order from dino direct. Ignore their rating and rather look at the actual reviews on reseller ratings. The bad reviews seem to follow the same trends of dishonest selling, while many of the good reviews are some of the worst fake engrish reviews I have seen. Even the text makes it quite obvious they are fake.

[rrodgers]

There is a Nikkor Lens Club as part of Pentax Forums. I recently posted some information on a fairly simple method of converting Nikkor lenses for use on Pentax K mount cameras. This involves making (or having made) a stainless steel ring. This provides proper registration of the lens - permitting focusing at infinity - and getting the lens to click/lock in place.

The following URL is the page where this post can be found: https://www.pentaxforums.com/forums/lens-clubs/60225-nikkor-lens-club-7.html

Best with the lens.